State Rep. John Macco, whose family runs a prominent flooring business in the district.

State Sen. Frank Lasee, who hails from the eastern part of the district.

Democrats point to the district's 2008 support for President Barack Obama, as well as its relatively inexpensive Green Bay media market and the state's competitive Senate race to argue they can put the seat in play. Party sources mention two main contenders:

Outagamie County Executive Tom Nelson, the former Democratic Assembly Leader and the 2010 lieutenant governor nominee. He's often mentioned as a likely gubernatorial candidate in 2018.

Jamie Wall, who lost to Ribble by 12 points in 2012. He ran for the Democratic nomination in 2006 but lost the primary to former Rep. Steve Kagen.

Ribble's retirement prompted the Rothenberg & Gonzales Report /Roll Call to change the rating of the district, which Obama carried by 9 points in 2008 and Mitt Romney carried by 4 points in 2012, from Safe Republican to Favored Republican .